the only time take out the batteries is when recharging it, or sending camera in for servicing
eh. for DSLR battery, what i read is that the camera will consume so so so little energy that it doesn't affect the battery much, in fact you will not be able to see depletion.
i don't take it too.
always inside the body/grip. and put it also together inside dry cab..
no problem so far
Canon EOS 40D | EF-S 15-85mm f/3.5-5.6 IS USM
i remove the battery after every use n put into dry box separately.
I usually leave the battery in the camera / battery grip if my camera is frequently used. If it's gonna be idle for a long time, let's say more than a week, I'd remove the battery. Further Lithium Ion batteries keep a healthy life if they are frequently charged
Remove and cap the battery
if u r using 1 or 2 a week it just leave it in the cam. use till the batt flat then recharge. the more u open the batt cover, the higher chance u mess up the contact, cover etc....
unless u decided not to use it for the next 2- 6 months, remove n leave it at 1/2 capacity. put in dry cabinet it can last a long time.
u might like to do a google search on article by battery university.
info might help.
Regarding the clock battery, it says in my camera manual that it needs the normal camera battery to charge it so that it can keep track of all those information and data in the CPU memory. 2 days of charging with the main battery will charge the clock battery to last for 3 months, after which you should install the main battery again to charge the clock battery. Pg 38 on the D300 manual, if anyone wants to know.
So if you're not gonna use the camera for very long, just remove the batteries, but remember to charge your clock battery if you don't want to go through all the clock setting and stuff. Haha!
I personally just leave it in.